Dual riser/single capillary viscometer

ABSTRACT

A blood viscosity measuring system and methods for measuring blood viscosity system monitors the change in height of two, oppositely-moving, columns of blood from the circulating blood of a patient and, given the dimensions of a capillary tube through which the blood flows, determines the blood viscosity over a range of shears, especially low shears. The system includes a tube set (disposable or nonisposable) that includes a pair of riser tubes, a capillary tube of predetermined dimensions that is coupled between the riser tubes (or that forms a portion of one riser tube) and a valve mechanism for controlling the circulating flow of blood from the patient into the riser tubes. Respective sensors monitor the movement of the columns of blood in each of the riser tubes and an associated microprocessor analyzes these movements, along with the predetermined dimensions of the capillary tube to determine the viscosity of the patient&#39;s circulating blood.

RELATED APPLICATIONS

This application is a Continuation-in-Part of application Ser. No.08/919,906, filed Aug. 28, 1997, (now U.S. Pat. No. 6,019,735) entitledVISCOSITY MEASURING APPARATUS AND METHOD OF USE, assigned to the sameAssignee as the present invention and whose entire disclosure isincorporated by reference herein.

BACKGROUND OF THE INVENTION

This invention relates generally to an apparatus and method formeasuring the viscosity of liquids, and more particularly, an apparatusand methods for measuring the viscosity of the blood of a living beingin-vivo and over a wide range of shears.

The importance of determining the viscosity of blood is wellknown.Fibropen. Viscosity and White Blood Cell Count Are Major Risk Factorsfor Ischemic Heart Disease, by Yarnell et al., Circulation, Vol. 83, No.3, March 1991; Postprandial Changes in Plasma and Serum Viscosity andPlasma Lipids and Lipoproteins After an Acute Test Meal, by Tangney, etal., American Journal for Clinical Nutrition, 65:36-40, 1997; Studies ofPlasma Viscosity in Primary Hyperligoproteinaemia, by Leonhardt et al.,Atherosclerosis 28, 29-40, 1977; Effects of Lipogroteins on PlasmaViscosity, by Seplowitz, et al., Atherosclerosis 38, 89-95, 1981;Hyperviscosity Syndrome in a Hypercholesterolemic Patient with PrimaryBiliary Cirrhosis, Rosenson, et al., Gastroenterology, Vol. 98, No. 5,1990; Blood Viscosity and Risk of Cardiovascular Events:the EdinburghArtery Study, by Lowe et al., British Journal of Hematology, 96,168-171, 1997; Blood Rheoloay Associated with Cardiovascular RiskFactors and Chronic Cardiovascular diseases: Results of an EpidemiologicCross-Sectional Study, by Koenig, et al., Angiology, The Journal ofVascular Diseases, November 1988; Importance of Blood Viscoelasticity inArteriosclerosis, by Hell, et al., Angiology, The Journal of VascularDiseases, June, 1989; Thermal Method for Continuous Blood-VelocityMeasurements in Large Blood Vessels. and Cardiac-Output Determination,by Delanois, Medical and Biological Engineering, Vol. 11, No. 2, March1973; Fluid Mechanics in Atherosclerosis, by Nerem, et al., Handbook ofBioengineering, Chapter 21, 1985.

Much effort has been made to develop apparatus and methods fordetermining the viscosity of blood. Theory and Design of DisposableClinical Blood Viscometer, by Litt et al., Biorheology, 25, 697-712,1988; Automated Measurement of Plasma Viscosity by Capillary Viscometer,by Cooke, et al., Journal of Clinical Pathology 41, 1213-1216, 1988; ANovel Computerized Viscometer/Rheometer by Jimenez and Kostic, Rev.Scientific Instruments 65, Vol 1, January 1994; A New Instrument for theMeasurement of Plasma-Viscosity, by John Harkness, The Lancet, pp.280-281, Aug. 10, 1963; Blood Viscosity and Raynaud's Disease, byPringle, et al., The Lancet, pp. 1086-1089, May 22, 1965; Measurement ofBlood Viscosity Using a Conicylindrical Viscometer, by Walker et al.,Medical and Biological Engineering, pp. 551-557, September 1976.

In addition, there are a number of patents relating to blood viscositymeasuring apparatus and methods. See for example, U.S. Pat. No.:3,342,063 (Smythe et al.); U.S. Pat. No. 3,720,097 (Kron); U.S. Pat. No.3,999,538 (Philpgt Jr.); U.S. Pat. No. 4,083,363 (Philpot); U.S. Pat.No. 4,149,405 (Ringrose); U.S. Pat. No. 4,165,632 (Weber, et. al.); U.S.Pat. No. 4,517,830 (Gunn, deceased, et. al.); U.S. Pat. No. 4,519,239(Kiesewetter, et. al.); U.S. Pat. No. 4,554,821 (Kiesewetter, et. al.);U.S. Pat. No. 4,858,127 (Kron, et. al.); U.S. Pat. No. 4,884,577(Merrill); U.S. Pat. No. 4,947,678 (Hori et al.); U.S. Pat. No.5,181,415 (Esvan et al.); U.S. Pat. No. 5,257,529 (Taniguchi et al.);U.S. Pat. No. 5,271,398 (Schlain et al.); and U.S. Pat. No. 5,447,440(Davis, et. al.).

The Smythe '063 patent discloses an apparatus for measuring theviscosity of a blood sample based on the pressure detected in a conduitcontaining the blood sample. The Kron '097 patent discloses a method andapparatus for determining the blood viscosity using a flowmeter, apressure source and a pressure transducer. The Philpot '538 patentdiscloses a method of determining blood viscosity by withdrawing bloodfrom the vein at a constant pressure for a predetermined time period andfrom the volume of blood withdrawn. The Philpot '363 patent discloses anapparatus for determining blood viscosity using a hollow needle, a meansfor withdrawing and collecting blood from the vein via the hollowneedle, a negative pressure measuring device and a timing device. TheRingrose '405 patent discloses a method for measuring the viscosity ofblood by placing a sample of it on a support and directing a beam oflight through the sample and then detecting the reflected light whilevibrating the support at a given frequency and lih, amplitude. The Weber'632 patent discloses a method and apparatus for determining thefluidity of blood by drawing the blood through a capillary tubemeasuring cell into a reservoir and then returning the blood backthrough the tube at a constant flow velocity and with the pressuredifference between the ends of the capillary tube being directly relatedto the blood viscosity. The Gunn '830 patent discloses an apparatus fordetermining blood viscosity that utilizes a transparent hollow tube, aneedle at one end, a plunger at the other end for creating a vacuum toextract a predetermined amount and an apertured weight member that ismovable within the tube and is movable by gravity at a rate that is afunction of the viscosity of the blood. The Kiesewetter '239 patentdiscloses an apparatus for determining the flow shear stress ofsuspensions, principally blood, using a measuring chamber comprised of apassage configuration that simulates the natural microcirculation ofcapillary passages in a being. The Kiesewetter '821 patent disclosesanother apparatus for determining the viscosity of fluids, particularlyblood, that includes the use of two parallel branches of a flow loop incombination with a flow rate measuring device for measuring the flow inone of the branches for determining the blood viscosity. The Kron '127patent discloses an apparatus and method for determining blood viscosityof a blood sample over a wide range of shear rates. The Merrill '577patent discloses an apparatus and method for determining the bloodviscosity of a blood sample using a hollow column in fluid communicationwith a chamber containing a porous bed and means for measuring the bloodflow rate within the column. The Hori '678 patent discloses a method formeasurement of the viscosity change in blood by disposing a temperaturesensor in the blood flow and stimulating the blood so as to cause aviscosity change. The Esvan '415 patent discloses an apparatus thatdetects the change in viscosity of a blood sample based on the relativeslip of a drive element and a driven element, which holds the bloodsample, that are rotated. The Taniguchi '529 patent discloses a methodand apparatus for determining the viscosity of liquids, e.g., a bloodsample, utilizing a pair of vertically-aligned tubes coupled togethervia fine tubes while using a pressure sensor to measure the change of aninternal tube pressure with the passage of time and the change of flowrate of the blood. The Bedingham '328 patent discloses an intravascularblood parameter sensing system that uses a catheter and probe having aplurality of sensors (e.g., an O₂ sensor, CO₂ sensor, etc.) formeasuring particular blood parameters in vivo. The Schlain '398 patentdiscloses a intra-vessel method and apparatus for detecting undesirablewall effect on blood parameter sensors and for moving such sensors toreduce or eliminate the wall effect. The Davis '440 patent discloses anapparatus for conducting a variety of assays that are responsive to achange in the viscosity of a sample fluid, e.g., blood.

Viscosity measuring methods and devices for fluids in general arewell-known. See for example, U.S. Pat. No.: 1,810,992 (Dallwitz-Wegner);U.S. Pat. No. 2,343,061 (Irany); U.S. Pat. No. 2,696,734 (Brunstrum etal.); U.S. Pat. No. 2,700,891 (Shafer); U.S. Pat. No. 2,934,944(Eolkin); U.S. Pat. No. 3,071,961 (Heigl et al.); U.S. Pat. No.3,116,630 (Piros); U.S. Pat. No. 3,137,161 (Lewis et al.); U.S. Pat. No.3,138,950 (Welty et al.); U.S. Pat. No. 3,277,694 (Cannon et al.); U.S.Pat. No. 3,286,511 (Harkness); U.S. Pat. No. 3,435,665 (Tzentis); U.S.Pat. No. 3,520,179 (Reed); U.S. Pat. No. 3,604,247 (Gramain et al.);U.S. Pat. No. 3,666,999 (Moreland, Jr. et al.); U.S. Pat. No. 3,680,362(Geerdes et al.); U.S. Pat. No. 3,699,804 (Gassmann et al.); U.S. Pat.No. 3,713,328 (Aritomi); U.S. Pat. No. 3,782,173 (Van Vessem et al.);U.S. Pat. No. 3,864,962 (Stark et al.); U.S. Pat. No. 3,908,441(Virloget); U.S. Pat. No. 3,952,577 (Hayes et al.); U.S. Pat. No.3,990,295 (Renovanz et al.); U.S. Pat. No. 4,149,405 (Ringrose); U.S.Pat. No. 4,302,965 (Johnson et al.); U.S. Pat. No. 4,426,878 (Price etal.); U.S. Pat. No. 4,432,761 (Dawe); U.S. Pat. No. 4,616,503 (Plungiset al.); U.S. Pat. No. 4,637,250 (Irvine, Jr. et al.); U.S. Pat. No.4,680,957 (Dodd); U.S. Pat. No. 4,680,958 (Ruelle et al.); U.S. Pat. No.4,750,351 (Ball); U.S. Pat. No. 4,856,322 (Langrick et al.); U.S. Pat.No. 4,899,575 (Chu et al.); U.S. Pat. No. 5,142,899 (Park et al.); U.S.Pat. No. 5,222,497 (Ono); U.S. Pat. No. 5,224,375 (You et al.); U.S.Pat. No. 5,257,529 (Taniguchi et al.); U.S. Pat. No. 5,327,778 (Park);and U.S. Pat. No. 5,365,776 (Lehmann et al.).

The following U.S. patents disclose viscosity or flow measuring devices,or liquid level detecting devices using optical monitoring: U.S. Pat.No. 3,908,441 (Virloget); U.S. Pat. No. 5,099,698 (Kath, et. al.); U.S.Pat. No. 5,333,497 (Br nd Dag A. et al.). The Virloget '441 patentdiscloses a device for use in viscometer that detects the level of aliquid in a transparent tube using photodetection. The Kath '698 patentdiscloses an apparatus for optically scanning a rotameter flow gauge anddetermining the position of a float therein. The Br nd Dag A. '497patent discloses a method and apparatus for continuous measurement ofliquid flow velocity of two risers by a charge coupled device (CCD)sensor.

U.S. Pat. No. 5,421,328 (Bedingham) discloses an intravascular bloodparameter sensing system.

A statutory invention registration, H93 (Matta et al.) discloses anapparatus and method for measuring elongational viscosity of a testfluid using a movie or video camera to monitor a drop of the fluid undertest.

The following publications discuss red blood cell deformability and/ordevices used for determining such: Measurement of Human Red Blood CellDeformability Using a Single Micropore on a Thin Si ₃N₄ Film, by Oguraet al, IEEE Transactions on Biomedical Engineering, Vol. 38, No. 8,August 1991; the Pall BPF4 High Efficiency Leukocyte Removal BloodProcessing Filter System, Pall Biomedical Products Corporation, 1993.

A device called the “Hevimet 40” has recently been advertised atwww.hevimet.freeserve.co.uk. The Hevimet 40 device is stated to be awhole blood and plasma viscometer that tracks the meniscus of a bloodsample that falls due to gravity through a capillary. While the Hevimet40 device may be generally suitable for some whole blood or blood plasmaviscosity determinations, it appears to exhibit several significantdrawbacks. For example, among other things, the Hevimet 40 deviceappears to require the use of anti-coagulants. Moreover, this devicerelies on the assumption that the circulatory characteristics of theblood sample are for a period of 3 hours the same as that for thepatient's circulating blood. That assumption may not be completelyvalid.

Notwithstanding the existence of the foregoing technology, a needremains for an apparatus and method for obtaining the viscosity of theblood of a living being in-vivo and over a range of shears and for theprovision of such data in a short time span.

OBJECTS OF THE INVENTION

Accordingly, it is the general object of the instant invention toprovide an apparatus and methods for meeting that need.

It is a further object of this invention to provide viscosity measuringan apparatus and methods for determining the viscosity of circulatingblood over a range of shear rates, especially at low shear rates.

It is still yet a further object of this invention to provide anapparatus and methods for determining viscosity of the circulating bloodof a living being (e.g., in-vivo blood viscosity measurement) withoutthe need to directly measure pressure, flow and volume.

It is yet another object of this invention to provide an indication ofthe viscosity of the circulating blood of a living being in a short spanof time.

It is yet another object of this invention to provide an apparatus andmethods for measuring the viscosity of the circulating blood of a livingbeing and with minimal invasiveness.

It is still yet another object of the present invention to provide anapparatus and methods for measuring the viscosity of the circulatingblood of a living being that does not require the use ofanti-coagulants, or other chemicals or biologically active materials.

It is still yet even another object of the present invention to providean apparatus and method for measuring the viscosity of blood of a livingbeing that does not require the blood to be exposed to atmosphere oroxygen.

It is still yet another object of the present invention to provide anapparatus and method for determining the viscosity of the circulatingblood contemporaneous with the diversion of the blood into a conveyingmeans (e.g., needle) when that means is coupled to, e.g., inserted into,the patient.

It is still yet another object of the present invention to provide anapparatus and methods for measuring the circulating blood viscosity of aliving being that comprises disposable portions for maintaining asterile environment, ease of use and repeat testing.

It is still yet another object of the present invention to provide ablood viscosity measuring apparatus and methods for determining thethixotropic point of the blood.

It is even yet another object of the present invention to provide anapparatus and methods for determining the yield stress of thecirculating blood.

It is moreover another object of the present invention to provide anapparatus and methods for detecting circulating blood viscosity toevaluate the efficacy of pharmaceuticals, etc., to alter blood viscosityof the circulating blood of a living being.

It is even yet another object of this invention to provide an apparatusand methods for detecting the viscosity of the circulating blood of apatient while negating the effects of venous pressure.

SUMMARY OF THE INVENTION

In accordance with one aspect of this invention an apparatus is providedfor effecting the viscosity measurement (e.g., in real-time) ofcirculating blood in a living being. The apparatus comprises: a lumenarranged to be coupled to the vascular system of the being; a pair oftubes having respective first ends coupled to the lumen for receipt ofcirculating blood from the being, and wherein one of the pair of tubescomprises a capillary tube having some known parameters; a valve forcontrolling the flow of circulating blood from the being's vascularsystem to the pair of tubes; and an analyzer, coupled to the valve, forcontrolling the valve to permit the flow of blood into the pair of tubeswhereupon the blood in each of the pair of tubes assumes a respectiveinitial position with respect thereto. The analyzer is also arranged foroperating the valve to isolate the pair of tubes from the being'svascular system and for coupling the pair of tubes together so that theposition of the blood in the pair of tubes changes. The analyzer is alsoarranged for monitoring the blood position change in the tubes andcalculates the viscosity based thereon.

In accordance with another aspect of this invention a method is providedfor determining the viscosity (e.g., in real-time) of circulating bloodof a living being. The method comprises the steps of: (a) providingaccess to the circulating blood of the living being to establish aninput flow of circulating blood; (b) dividing the input flow ofcirculating blood into a first flow path and a second flow path intowhich respective portions of the input flow pass and wherein one of thefirst or second flow paths includes a passageway portion having someknown parameters; (c) isolating the first and second flow paths from theinput flow and coupling the first and second flow paths together so thatthe position of the blood in each of the flow paths changes; (d)monitoring the blood position change in the first and second flow pathsover time; and (e) calculating the viscosity of the circulating bloodbased on the blood position change and on selected known parameters ofthe passageway portion.

In accordance with still another aspect of this invention an apparatusis provided for effecting the viscosity measurement (e.g., in real-time)of circulating blood in a living being. The apparatus comprises: a lumenarranged to be coupled to the vascular system of the being; a pair oftubes having respective first ends and second ends wherein the firstends are coupled together via a capillary tube having some knownparameters; a valve for controlling the flow of circulating blood fromthe being's vascular system to the pair of tubes wherein the valve iscoupled to a second end of one of the pair of tubes and is coupled tothe lumen; and an analyzer, coupled to the valve, for controlling thevalve to permit the flow of blood into the pair of tubes whereupon theblood in each of the pair of tubes assumes a respective initial positionwith respect thereto. The analyzer also is arranged for operating thevalve to isolate the pair of tubes from the being's vascular system sothat the position of the blood in the pair of tubes changes. Theanalyzer also is arranged for monitoring the blood position change inthe tubes and calculating the viscosity of the blood based thereon.

In accordance with yet another aspect of this invention a method isprovided for determining the viscosity (e.g., in real-time) ofcirculating blood of a living being. The method comprises the steps of:(a) providing access to the circulating blood of the living being toform an input flow of circulating blood; (b) directing the input flowinto one end of a pair of tubes coupled together via a passageway havingsome known parameters whereby the input flow passes through a first oneof the pair of tubes, through the passageway and into a first portion ofa second one of the pair of tubes in order to form respective columns inthe first and second tubes; (c) isolating the respective columns fromthe input flow so that the position of the blood in each of the columnschanges; (d) monitoring the blood position change in the respectivecolumns of blood over time; and (e) calculating the viscosity of thecirculating blood based on the blood position change and on selectedknown parameters of the passageway.

DESCRIPTION OF THE DRAWINGS

Other objects and many of the intended advantages of this invention willbe readily appreciated when the same becomes better understood byreference to the following detailed description when considered inconnection with the accompanying drawings wherein:

FIG. 1 is a block diagram of the dual riser/single capillary (DRSC)viscometer;

FIG. 2 is a front view of one embodiment of the DRSC viscometerdepicting the respective housings for the blood receiving means, withits door opened, and the analyzer/output portion;

FIG. 3 is a side view of the embodiment of FIG. 2;

FIG. 4 is a functional diagram of the DRSC viscometer just prior tomaking a viscosity test run;

FIG. 5 is a functional diagram of the DRSC viscometer during theviscosity test run;

FIG. 6 depicts a graphical representation of the respective columns offluid in the riser tubes of the DRSC viscometer during the viscositytest run;

FIGS. 7A-7C depict the operation of the valve mechanism of the DRSCviscometer just prior to, and during, the viscosity test run;

FIG. 8 is a block diagram for the DRSC viscometer which detects movementof the column of fluid in each of the riser tubes using various types ofsensors;

FIGS. 9A-9B comprise a flow chart of the operation of the DRSCviscometer;

FIG. 10A depicts a graphical representation of the viscosity of a livingpatient's circulating blood plotted for a range of shear rates;

FIG. 10B depicts a graphical representation of the logarithm of theviscosity of a living patient's circulating blood plotted against thelogarithm of shear rates;

FIG. 11 depicts an implementation of the capillary and riser tubeportion of the blood receiving means;

FIG. 12 is a partial cross-sectional view taken along line 12—12 of FIG.11.

FIG. 13 is a block diagram of a second more preferred dual riser/singlecapillary (DRSC) viscometer;

FIG. 14 is a front view of the second embodiment of the DRSC viscometerdepicting the respective housings for the blood receiving means, withits door opened, and the analyzer/output portion;

FIG. 15 is a functional diagram of the second embodiment of the DRSCviscometer just prior to making a viscosity test run;

FIG. 16 is a functional diagram of the second emobidment of the DRSCviscometer during the viscosity test run;

FIGS. 17A-17C depict the operation of the valve mechanism of the secondembodiment of the DRSC viscometer just prior to, and during, theviscosity test run;

FIG. 18 is a block diagram for the second embodiment of the DRSCviscometer which detects movement of the column of fluid in each of theriser tubes using various types of sensors;

FIGS. 19A-19B comprise a flow chart of the operation of the secondembodiment of the DRSC viscometer;

FIG. 20 depicts an implementation of the capillary and riser tubeportion of the blood receiving means for the second embodiment of theDRSC viscometer; and

FIG. 21 is a partial cross-sectional view taken along line 21—21 of FIG.20.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

As stated previously, the present application is a Continuation-in-Partof Co-Pending application Ser. No. 08/919,906 (now U.S. Pat. No.6,019,735) filed Aug. 28, 1997, entitled VISCOSITY MEASURING APPARATUSAND METHOD OF USE, assigned to the same Assignee as the presentinvention and whose entire disclosure is incorporated by referenceherein. For measuring the viscosity of circulating blood, includingwhole blood, of a living being, the apparatus and method as disclosed inapplication Ser .No. 08/919,906 now U.S. Pat. No. 6,019,735 aregenerally preferable. To negate venous pressure effects at low shearrates, cuffing the living being, or other suitable means, may be usedwith that apparatus and method.

An alternative apparatus and method of the present invention to negatepressure at low shear rates for measuring the viscosity of circulatingblood, including whole blood, of a living being is shown generally at 20in FIG. 1. The dual riser/single capillary (DRSC) viscometer 20basically comprises a blood receiving means 22 and an analyzer/outputportion 24. The patient is coupled to the DRSC viscometer 20 through acirculating blood conveying means 26, e.g., a needle, an IV needle, anin-dwelling catheter, etc., or any equivalent structure that can conveycirculating blood from a patient to the DRSC viscometer 20. As will bediscussed in detail later, the analyzer/output portion 24 provides adisplay 28 for presenting the viscosity information, as well as otherinformation to the operator. The analyzer/output portion 24 may alsoprovide this information to other suitable output means 30, such as adatalogger 32, other computer(s) 34, a printer 36, a plotter 38, remotecomputers/storage 40, to the Internet 42 or to other on-line services44.

The blood receiving means 22 basically comprises a valve mechanism 46coupled to a first riser tube R1 on one side and coupled to a secondriser tube R2 via a capillary tube 52 on the other side. The capillarytube 52 is of small uniform inside diameter, e.g., 60 mm-length, 0.8 mminside diameter. When the circulating blood conveying means 26(hereinafter the “CBCM 26”) is coupled to the blood receiving means 22,the valve mechanism 46 controls the flow of blood into the receivingmeans 22, as will be discussed in detail later. Each of the riser tubesR1 and R2 are preferably the same dimensions (e.g., 12 inch long, 2 mminside diameter).

It should be understood that the blood receiving means 22 may bedisposable or non-disposable. As will be discussed in detail later,where the blood receiving means 22 are disposable, the components (valvemechanism 46, riser tubes R1 and R2 and capillary tube 52) arereleasably secured in a blood receiving means housing that can bequickly and easily inserted, used during the viscosity test run and thenquickly and easily removed for disposal; another disposable bloodreceiving means 22 is then inserted in preparation for the nextviscosity test run. On the other hand, where the blood receiving means22 is non-disposable, the components (valve mechanism 46, riser tubes R1and R2 and capillary tube 52) can be thoroughly washed and cleaned inplace in preparation for the next viscosity test run.

It should be understood that the capillary tube 52 does not necessarilyhave to be an elongated tube but may comprise a variety ofconfigurations such as a coiled capillary tube.

The analyzer/output portion 24 basically comprises a first column leveldetector 54, a second column level detector 56, a processor 58, thedisplay 28, a bar code reader 78, an environmental control unit 80, anda first battery B1 and a second back-up battery B2. The first columnlevel detector 54 monitors the level of blood in the first riser tube R1and the second column level detector 56 monitors the level of blood inthe second riser tube R2. The processor 58 (e.g., a “386” microprocessoror greater, or any equivalent) is arranged to analyze the data from thedetectors 54/56 and calculate the blood viscosity therefrom, as willalso be discussed in detail later. Furthermore, the processor 58 alsocontrols the display 28 for providing the viscosity information and theother information to the operator as well as to the other output means30. The processor 58 also controls the valve mechanism 46 based on thedata from the detectors 54/56, as will be discussed later. Battery BIprovides all of the requisite power to the analyzer/output portion 24,with battery B2 serving as a back-up power supply. The bar code reader78 and the environmental control unit 80 will be described later.

As shown more clearly in FIGS. 2-3, the preferred embodiment of the DRSCviscometer 20 comprises the blood receiving means 22 and theanalyzer/output portion 24 contained in respective housings 60 and 62,each of which can be releasably secured to a common frame, e.g., aconventional intravenous (IV) pole 48. In this configuration, theanalyzer/output portion 24 can be positioned in an inclined orientation(see FIG. 3) to facilitate user operation and viewing of the display 28.However, it should be understood that the respective housingconstructions are exemplary, and others can be incorporated withoutlimiting the scope of this invention.

The display 28 may comprise any suitable conventional devices, e.g., anELD (electroluminescent display) or LCD (liquid crystal display) thatpermits the visualization of both text and graphics. The resolution ofthis display 28 is preferably 800×600 VGA or above. Furthermore, whilethe preferred embodiment utilizes a touch screen display whichincorporates, among other things:

graphical display 61

instruction, and/or data, display 65 (which also includes the commandline display shown as “RUN TEST”; e.g., “TESTING”, “TEST IN PROGRESS,”etc.)

alphanumeric keypad 68

emergency stop button 70

battery status indicators, 72A and 72B

function buttons 74,

it should be understood that any equivalent display device is within thebroadest scope of the invention. Thus, any number of user interfaces andbuttons may be available through the display 28. Therefore the invention20 is not limited to the embodiment that is shown in FIG. 2. Moreover,the display 28 can be operated to minimize or maximize, or overlay anyparticular graphic or text screen, as is available in any conventionalobject-oriented operating system, such as Microsoft® WINDOWS.

The lower housing 60 comprises the blood receiving means 22 and the twocolumn level detectors 54 and 56. In the preferred embodiment, eachcolumn level detector 54/56 comprises an LED (light emitting diode)array 64 and a CCD (charge coupled device) 66 located on opposite sidesof each riser tube R1 ad R2. When the column level detectors 54/56 areoperating, each LED array 64 illuminates its respective riser tube R1 orR2, and depending on whether there is fluid in the column, variouspixels in the CCD 66 will either detect the light from the LED array 64(no fluid in the column, thereby permitting the light to pass throughthe riser tube) or not (fluid is present and is blocking the passage oflight from the LED array 64). The pixel data of each CCD 66 is passed tothe analyzer/output 24 through conventional wire harnesses (not shown)for use by the processor 58. Furthermore, power for the LED arrays 64and the CCDs 66 is provided via these wire harnesses from the batteriesB1/B2, if the batteries are contained in the analyzer/output housing 62.

Where the blood receiving means 22 is disposable, it is releasablysecured in the housing 60 such that once a test run is completed and/ora new patient is to be tested, all of the lumens (e.g., the tube 50, thecapillary 52, the riser tubes R1 an R2 and the valve mechanism 46) canbe easily/quickly removed, disposed of and a new set inserted. Forexample, brackets 47 (FIG. 2) may be used to releasably secure the upperportions of the riser tubes R1 and R2 and the lower portions of theriser tubes R1 and R2; the valve mechanism 46 comprises a port 49 thatfits snugly into an opening (not shown) in the bottom wall of thehousing 60. The column level detectors 54/56 are preferably notremovable from the housing 60. A door 76 (which can be vertically orhorizontally hinged to the housing 60) is provided to establish adarkened environment during the test run. The door 76 also supports thebar code reader 78, mentioned earlier. This bar code reader 78automatically reads a bar code (not shown) that is provided on one ofthe riser tubes (e.g., R2). The bar code contains all of thepredetermined data regarding the characteristics of the capillary tube52 (e.g., its length and diameter) and the characteristics of the risertubes R1 and R2. This information is passed to the processor 58 which isthen used to determine the viscosity, as will be discussed in detaillater. The bar code reader 78 passes this information to the processor58 via the wire harnesses discussed earlier. It should be understoodthat the location (on the door 76) of the bar code reader 78 isexemplary only and that other locations within the unit are encompassedby the scope of the invention.

It should be understood that the brackets 47 do not interfere in any waywith the column level detection since the movement of blood in each ofthe corresponding riser tubes R1 and R2 that is being monitored duringthe viscosity test run is in between the upper and lower bracket 47pairs.

The door 76 also supports an environmental control unit 80 (e.g., aheater, fan and/or thermostat) such that when it is closed inpreparation for the test, the capillary tube 52 is then heated (orcooled) and maintained throughout the test run at the same temperatureand environment as the patient. Prior to the run, the patient'stemperature is taken and the operator enters this temperature (via thetouch screen display 28). The environmental control unit 80 thenoperates to achieve and maintain this temperature. It should be notedthat it is within the broadest scope of this invention to include aenvironmental control unit 80 that achieves and maintains the entireblood receiving means 22 at the patient's temperature during the run.Power to the bar code reader 78 and temperature control unit 80 isprovided by the analyzer/output 24 through the wire harnesses (notshown) discussed previously.

One exemplary implementation of the blood receiving means 22 is shown inFIGS. 11-12. In particular, the riser tubes R1 and R2 (e.g.,injection-molded pieces) have integral elbows 50A and 50B that areinserted into respective ports (not shown) of the valve mechanism 46(e.g., a single, 3-way stop cock valve). Prior to inserting the elbowportion 50B of riser R2 into its corresponding valve mechanism port, acapillary insert 53 having internal capillary 52, is positioned insidethe riser tube R2. As shown most clearly in FIG. 12, the capillaryinsert 53 comprises a tapered entry port 55 and a tapered exit port 57to minimize any turbulence as the circulating blood passes from thevalve mechanism through the elbow 50B and up into riser tube R2.

The batteries B1/B2 may comprise a 12VDC, 4 amp-hour batteries, or anyequivalent power supply (e.g., batteries used in conventional lap-topcomputers such as lithium ion batteries). The display 28 provides thestatus indicators 72A/72B for each battery in the DRSC viscometer 20. Inparticular, when the DRSC viscometer 20 is operating off of battery B1,the two battery indicators 72A/72B appear on the display 28. However,once battery B1 is depleted, the battery B1 indicator 72A disappears andthe battery B2 indicator 72B blinks to warn the operator that the DRSCviscometer 20 is now operating off of the back-up battery B2 andre-charge of battery B1 is necessary.

The concept of viscosity determination using the DRSC viscometer 20 isto monitor the change in height of two, oppositely-moving, columns ofblood from the circulating blood of a patient and given the dimensionsof a capillary through which one of the columns of blood must flow. TheDRSC viscometer 20 accomplishes this by operating the valve mechanism 46to first establish an optimum separation distance between the twocolumns of blood 82 and 84 in the respective riser tubes R1 and R2 (FIG.4). Once established, the DRSC viscometer 20, via its valve mechanism46, couples these two columns of blood 82/84 together and permits themto reach equilibrium while monitoring the movement of the two columnsblood 82/84 (FIG. 5).

In particular, as shown in FIG. 4, continuous blood flow from thepatient is permitted to flow from the CBCM 26, through the valvemechanism 46, and into both riser tubes R1 and R2. During this flow, thecolumn level detectors 54/56 monitor the height of each respectivecolumn of blood. When the optimum separation distance is achieved, i.e.,when the column of blood in riser tube R1 reaches h_(1i) and the columnof blood in riser tube R2 reaches h_(2i), the valve mechanism 46 stopsthe flow of blood from the CBCM 26 and simultaneously couples thecolumns of blood together (FIG. 5). As a result, the column of blood inriser R1 falls and the column of blood in riser R2 climbs toward a finalequilibrium value, h₂₈(which, as will be discussed later, is actually anoffset known as “Δh”). It is the detection of these oppositely movingcolumns of blood (FIG. 5), also known as “h₁(t)” and “h₂(t)”, which isimportant for blood viscosity determination, as will be discussed later.The graphical representation of h₁(t) and h₂(t) is shown in FIG. 6.

It should be understood that the optimum separation distance, i.e.,h_(1i)-h_(2i), as well as the dimensions of the capillary tube 52,avoids any oscillations of the columns of blood at the end of theviscosity test run. In other words, these two factors provide for theflat appearance of each of the plots h₁(t) and h₂(t) at the end of theviscosity test run, as shown in FIG. 6.

FIGS. 7A-7C depict a typical sequence of how the valve mechanism 46establishes the pre-test run columns of blood (FIG. 4) and the test runcolumns of blood (FIG. 5). The valve mechanism 46 comprises a single,3-way stop cock valve. The valve may comprise a solenoid (e.g., 500 mAsolenoid, or stepper motor, etc., indicated by valve driver 86) that ispulsed by the processor 58 to operate the valve in the appropriatedirection. In particular, the processor 58 commands rotation of thevalve by issuing a positive or negative pulse to the solenoid. Forexample, to receive patient circulating blood flow into the DRSCviscometer 20 initially, the valve driver 86 configures the valve toallow circulating blood to enter both riser tubes R1 and R2 throughrespective tubing 13 and 14 (FIG. 7A). The column level detectors 54/56are monitoring their respective columns of blood 82 and 84 during thistime. Should the column of blood pre-test level h_(1i) be reached first,the processor 58 issues a positive pulse to the valve driver 86 to closeoff flow to riser tube R1 (FIG. 7B); alternatively, should the column ofblood pre-test level h_(2i) be reached first, the processor 58 issues anegative pulse to close off flow to riser tube R2 while continuing toallow circulating blood flow into riser tube R1 (not shown). Finally, tocouple the two riser tubes R1 and R2 together while isolating them fromthe circulating blood flow of the patient, the processor 58 commands thevalve driver 86 to the position shown in FIG. 7C.

As shown in FIG. 8, it is within the broadest scope of the invention toinclude any means and/or method for detecting the movement of thecolumns of blood 82/84 in the riser tubes R1 and R2 and, as such, is notlimited to the LED array 64/CCD 66 arrangement nor even limited to thecolumn level detectors 54/56. In fact, the following type of physicaldetections (indicated by “SENSOR 1” and “SENSOR 2” in FIG. 8) arecovered by the present invention:

d(Weight)/dt: the change in weight of each column of fluid with respectto time using a weight detecting means for each column of fluid as thesensor; e.g., w₁(t)-w₂(t);

d(Pressure)/dt: the change in pressure of each column of fluid withrespect to time using a pressure transducer located at the top of eachcolumn of fluid; e.g., p₁(t)-p₂(t);

time of flight: the length of time it takes an acoustic signal to beemitted from a sensor (e.g., ultrasonic) located above each column offluid and to be reflected and return to the sensor; e.g., time offlight₁(t)-time of flight₂(t);

d(Volume)/dt: the change in volume of each column of fluid with respectto time; e.g., V₁(t)-V₂(t);

d(Position)/dt: the change in position of each column level using adigital video camera; e.g., Pos₁(t)-Pos₂(t);

d(Mass)/dt: the change in mass with respect to time for each column offluid; e.g., m₁(t)-m₂(t).

FIGS. 9A-9B comprise a flowchart of the detailed operation of the DRSCviscometer 20 to determine the viscosity of a patient's circulatingblood flow. The overall time of the test run is approximately 3 minuteswith the CCDs 66. When the pixel values of the CCDs 66 are no longerchanging, the DRSC 20 determines that Δh has been reached and the testrun is terminated.

As discussed earlier, the concept of viscosity determination using theDRSC viscometer 20 is to monitor the change in height of two,oppositely-moving, columns of blood from the circulating blood of apatient and given the dimensions of a capillary through which one of thecolumns of blood must flow.

In particular, for non-Newtonian fluids, as is blood, the viscosityvaries with shear rate, however, Hagen-Poiseuille flow within thecapillary still holds for steady or quasi-steady laminar flow. For afluid that is well-correlated with a non-Newtonian power law viscositymodel, the capillary pressure drop and flow rate are related as follows:$\begin{matrix}{{\Delta \quad P_{c}} = {\frac{4{kL}_{c}{\overset{.}{\gamma}}^{n}}{\varphi_{c}} = {\frac{4{kL}_{c}}{\varphi_{c}}{{\left( \frac{{3n} + 1}{n} \right)\frac{\begin{matrix}{8Q}\end{matrix}}{{\pi\varphi}_{c}^{3}}}}^{n}}}} & (1)\end{matrix}$

where the shear rate, {dot over (γ)} is related to the capillary flowrate by: $\begin{matrix}{\overset{.}{\gamma} = {\left( \frac{{3n} + 1}{n} \right)\frac{\begin{matrix}{8Q}\end{matrix}}{{\pi\varphi}_{c}^{3}}}} & (2)\end{matrix}$

where the power law viscosity is defined as:

μ=k|{dot over (γ)}| ⁻¹  (3)

and where

ΔP_(c)=capillary tube pressure drop (Pa)

L_(c)=length of capillary tube (m)

Q=volumetric flow rate (m³/s)

k=consistency index (a constant used in capillary viscometry)—that isdetermined;

n=power law index (another constant used in capillary viscometry)—thatis determined;

φ_(c)=capillary tube diameter (m)

μ=fluid viscosity (centipoise, CP)

{dot over (γ)}=shear rate (s⁻¹)

Since blood, a non-Newtonian fluid, is well-characterized with a powerlawviscosity model, Equation (1) can be re-written as:

$\begin{matrix}{{\rho \quad {g\left( {h_{1} - h_{2}} \right)}} = {{\frac{4{kL}_{c}}{d_{c}}\left\{ {2{\left( \frac{{3n} + 1}{n} \right) \cdot \left( \frac{\varphi_{r}^{2}}{\varphi_{c}^{3}} \right)}\left( \frac{h}{t} \right)} \right\}^{n}} + {\Delta \quad h\quad \rho \quad g}}} & (4)\end{matrix}$

where

ρ=blood density;

g=gravitational constant;

h₁=instantaneous height of the column of blood in riser R1

h₂=instantaneous height of the column of blood in riser R2

φ_(c)=inside diameter of the capillary tube

d_(r)=inside diameter of riser tube and where φ_(c)<<<φ_(r)

Δh=an offset due to yield stress of the blood and is a property ofblood.

It should be noted that the length of the capillary tube L_(c) isassumed large such that any friction forces in the riser tubes R1 and R2and connecting fluid components can be ignored. In addition, thediameter of the riser tubes R1 and R2 are equal.

By integrating both sides of Equation (4) with respect to time, the needto determine $\frac{h}{t}$

is eliminated, which yields: $\begin{matrix}{{h_{1} - h_{2} - {\Delta \quad h}} = {- \left\{ {{\left( \frac{n - 1}{n} \right)\alpha \quad t} + \left( {{\Delta \quad h} - h_{0}} \right)^{\frac{n - 1}{n}}} \right\}^{\frac{n}{n - 1}}}} & (5)\end{matrix}$

where

h₀=h₁(t)-h₂(t) at t=0) i.e., −h₀=h_(1i)-h_(2i); and $\begin{matrix}{\alpha = {{- \frac{1}{2}}\left( \frac{4{kL}_{c}}{\rho \quad {gd}_{c}} \right)^{n}\left( \frac{n}{{3n} + 1} \right)\left( \frac{\varphi_{c}^{3}}{\varphi_{r}^{2}} \right)}} & (6)\end{matrix}$

In order to determine the viscosity, it is necessary to determine thevalues for k and n using curve fitting based on the test run data. Inparticular, the following procedure is used:

1) Conduct a test run and obtain all h₁(t) and h₂(t) data;

2) Fit curves through the data to obtain symbolic expressions for h₁(t)and h₂(t);

3) Determine all h₁(t)-h₂(t) data, as well as Δh;

3) Assume values for the power law parameters k and n;

4) Calculate the following error values for all data points:$\begin{matrix}{{Error} = {{\left( {h_{1} - h_{2} - {\Delta \quad h}} \right) - \left\{ {{\left( \frac{n - 1}{n} \right)\alpha \quad t} + \left( {{\Delta \quad h} - h_{0}} \right)^{\frac{n - 1}{n}}} \right\}^{\frac{n}{n - 1}}}}} & (7)\end{matrix}$

6) Sum the error values for all data points;

7) Iterate to determine the values of k and n that minimize the errorsum; and

8) Use the determined k and n values in Equations (2) and (3) tocalculate viscosity. FIG. 10A depicts a graphical representation of theviscosity of the patient's circulating blood versus a range of shearrates and FIG. 10B depicts a logarithmic depiction of viscosity versusshear rate. It should be understood that the curves depicted in thosegraphs are identical mathematically and that the DRSC viscometer 20disclosed above ensures greater accuracy than existing technology.

A combined handle/filter assembly (not shown) could be used at the topof the riser tubes R1 and R2. This assembly permits the introduction ofan inert gas at atmospheric pressure into the riser tubes R1 and R2above the respective column of fluids. In addition, this assembly actsas a handle for the insertion and removal of the blood receiving means22 when a disposable blood receiving means 22 is utilized.

It should also be understood that the locations of many of thecomponents in the blood receiving means 22 are shown by way of exampleonly and not by way of limitation. For example, the capillary 52 can bepositioned horizontally or vertically; the valve mechanism 46 does notnecessarily have to be located at the elbow portions 50A/50B of theriser tubes R1 and R2. It is within the broadest scope of the inventionto include various locations of the components within the bloodreceiving means 22 without deviating from the invention. In fact, thenext embodiment discussed below utilizes such various locations.

In FIGS. 13-21, there is shown a more preferred embodiment 120 of theDRSC viscometer described heretofore. This second embodiment 120 for allintents and purposes is the same as the first embodiment 20 except forthe location of the valve mechanism 46, the use of a vacutainermechanism 101, the position of the capillary tube 52 and the requisitevolume of blood that is used in the blood receiving means. As a result,the equations (i.e., Equations 1-7) governing the operation of thissecond embodiment 120 and the plots concerning the column levels' timeresponse and viscosity (i.e., FIGS. 6, 10A and 10B) are similar and willnot be repeated here. Thus, the common details of the construction andoperation of embodiment 120 will not be reiterated. Furthermore, asstated previously with respect to the embodiment 20, the capillary tube52 used in the embodiment 120 does not necessarily have to be anelongated tube but may comprise a variety of configurations such as acoiled capillary tube.

As can be seen in FIG. 13, the embodiment 120 comprises a bloodreceiving means 122 and the analyzer/output portion 24. As with theblood receiving means 22 described earlier, the blood receiving means122 can be disposable or re-usable. As an example of a disposable bloodreceiving means 122, a friction-type fitting 147 (see FIG. 14)releasably secures the top end of riser tube R2 into the housing 60while the valve mechanism 46 is friction-fitted at the top of the risertube R1 into the housing 60. Thus, to remove the disposable bloodreceiving means 122, the operator need only disengage the fitting 147and the valve mechanism 46 friction fit.

The blood receiving means 122 comprises the valve mechanism 46 that isnow located at the top of riser tube R1 and the capillary tube 52 hasbeen located between the two riser tubes R1 and R2. In addition, avacutainer mechanism 101 has been added to the blood receiving means122. The vacutainer mechanism 101 permits the retrieval of a sample ofthe first blood to reach the blood receiving means 122 for subsequentblood analysis (e.g., hematocrit studies). However, it should beunderstood that the vacutainer mechanism 101 does not form any part ofthe viscosity determination and does not impede, in any way, theoperation of the DRSC viscometer 120 in determining blood viscosityaccording to that described with respect to the embodiment 20. In fact,the vacutainer mechanism 101, as will be described below, disengagesfrom the valve mechanism 46 before the viscosity test run begins.

The vacutainer mechanism 101 comprises vacutainer 107 that ispositionable by a vacutainer driver 109. Operation of the vacutainermechanism 101 is depicted in FIGS. 15, 16, 17A-17B and flowcharts FIGS.19A-19B. In particular, as shown most clearly in FIG. 17A, when thedetector 103 (e.g., a photodetector, photo-eye, etc.) detects the firstor initial portion of the input blood from the patient (via the CBCM26), the detector 103 alerts the microprocessor 58 which activates thevacutainer driver 109 to drive the vacutainer 107 towards the puncturingmeans 111 (e.g., needle, FIG. 15) on the valve mechanism 46 whichpunctures a piercable surface of the vacutainer 107. Simultaneously, theprocessor 58 commands the valve driver 86 to place the valve in thefirst position (as shown in FIG. 17A). As a result, the first or initialportion of the input blood flow is captured in the vacutainer 107. Aftera fixed time, t_(f), has elapsed, the processor 58 commands thevacutainer driver 109 to disengage the vacutainer 107 from thepuncturing means 111. With this initial portion of the input blood flowcaptured in the vacutainer 107, the operator can remove the vacutainer107 from the driver 109 and then presented to a separate analyzingmechanism either on-site or remotely-located.

Simultaneous with the processor 58 commanding the vacutainer driver 109to disengage the vacutainer 107 from the puncturing means 111, theprocessor 58 also commands the valve driver 86 to move the valve intothe second position (FIG. 17B). As a result, the input blood flow entersinto the top of the riser tube R2, down the riser tube R2, through thecapillary 52 and up into riser tube R1. The column level detectors 54and 56 monitor the blood columns in each riser. When column leveldetector 56 detects a predetermined level, h_(sv), it informs theprocessor 58. The h_(sv) is an exact value that corresponds to an exactvolume of blood such that when the column of blood in riser tube R2reaches h_(2i), (FIGS. 17B and 17C), the column of blood in riser R1will be at h_(1i). Therefore, when column level detector 56 detects thath_(sv) has been reached, the processor 58 activates the valve driver 86to rotate the valve into the third position (FIG. 17C), therebyisolating the two columns of blood from the input blood flow whilesimultaneously beginning the viscosity test run. This viscosity test runis similar to that described earlier with respect to embodiment 20 and,as such, will not be repeated here.

One exemplary implementation of the blood receiving means 122 is shownin FIGS. 20-21. In particular, the riser tubes R1 and R2 (e.g.,injection-molded pieces) have integral elbows 50A and 50B that areinserted into respective ends of a capillary element 153. In particular,each end of the capillary element 153 forms a form fitting sleeve thatslides over each end of the elbows 50A and 50B. As shown most clearly inFIG. 21, the capillary element 153 comprises a tapered entry port 155and a tapered exit port 157 to minimize any turbulence as thecirculating blood passes from the end of the elbow 50A into thecapillary element 153 and then into the elbow 50B and up into riser tubeR2.

It should be pointed out that the “blood receiving” means of allembodiments disclosed herein are merely exemplary of variouscombinations of components, such as riser tubes, etc., which can takevarious other forms than those specifically disclosed herein.

As shown in FIG. 18, it is within the broadest scope of the invention toinclude any means and/or method for detecting the movement of thecolumns of blood in the riser tubes R1 and R2 and, as such, is notlimited to the LED array 64/CCD 66 arrangement nor even limited to thecolumn level detectors 54/56. In fact, the following type of physicaldetections (indicated by “SENSOR 1” and “SENSOR 2” in FIG. 18) arecovered by the present invention:

d(Weight)/dt: the change in weight of each column of fluid with respectto time using a weight detecting means for each column of fluid as thesensor; e.g., w₁(t)-w₂(t);

d(Pressure)/dt: the change in pressure of each column of fluid withrespect to time using a pressure transducer located at the top of eachcolumn of fluid; e.g., p₁(t)-p₂(t);

time of flight: the length of time it takes an acoustic signal to beemitted from a sensor (e.g., ultrasonic) located above each column offluid and to be reflected and return to the sensor; e.g., time offlight₁(t)-time of flight₂(t);

d(Volume)/dt: the change in volume of each column of fluid with respectto time; e.g., V₁(t)-V₂(t);

d(Position)/dt: the change in position of each column level using adigital video camera; e.g., Pos₁(t)-Pos₂(t);

d(Mass)/dt: the change in mass with respect to time for each column offluid; e.g., m₁(t)-m₂(t).

It should be understood that although the above description for bothembodiments 20 and 120 concern a power law model, it is within thebroadest scope of the DRSC viscometers 20 and 120 to determine viscosityusing other curve fitting models such as Casson and Carreau.

The CCDs 66 may be any conventional device. One particularly suitableone is available from ScanVision Inc. of San Jose, Calif. That CCD is of300 dpi-83 μ pixel resolution. The ScanVision Inc. CCD utilizesconventional CCD acquisition software. The LED arrays 64 can beimplemented with a variety of light sources, including fiber opticlines.

Furthermore, the door 76 of the housing 60 can be configured to behinged along the bottom of the housing 60 so as to swing down in orderto gain access to the blood receiving means 22 or 122.

It should be understood that it is within the broadest scope of theinvention 20 and 120 to include auxiliary pressure (e.g., a pressuresource such as a pump) as the motive force for moving the columns ofblood 82/84 during the test run, as opposed to venting each of the risertubes R1 and R2 to the ambient atmosphere.

It should be further understood that although the display 28 provides anefficient means for conveying the viscosity data to the user, thebroadest scope of the DRSC viscometers 20 and 120 does not require thedisplay 28. Rather, as long as the viscosity data is available to anyoutput means 30, the objectives of the present invention are met.Furthermore, it should be understood that the analyzer/output portion 24in embodiments 20 and 120 can accomplished by a any laptop personalcomputer and is not limited in any way by that which is depicted inFIGS. 2-3.

The blood receiving means 22 and 122 of the respective embodiments 20and 120 are typically located to be at a position that is lower than thepatient's heart. By doing this, gravity assists the venous pressure inconveying the circulating blood to the blood receiving means 22/122, butthis also prevents any backflow of blood into the patient during thepreliminary hook up and viscosity test run.

It should be understood that where a re-usable blood receiving means 22is used in embodiment 20, or where a re-usable blood receiving means 122is used in embodiment 120, the step “insert disposable set” in FIG. 9Band FIG. 19B, respectively, is omitted.

Without further elaboration, the foregoing will so fully illustrate ourinvention and others may, by applying current or future knowledge,readily adapt the same for use under various conditions of service.

We claim:
 1. An apparatus for effecting the viscosity measurement ofcirculating blood in a living being, said apparatus comprising: a lumenarranged to be coupled to the vascular system of the being; a pair oftubes having respective first ends coupled to said lumen for receipt ofcirculating blood from the being, one of said pair of tubes comprising acapillary tube having some known parameters; a valve for controlling theflow of circulating blood from the being's vascular system to said pairof tubes; and an analyzer, coupled to said valve, for controlling saidvalve to permit the flow of blood into said pair of tubes whereupon theblood in each of said pair of tubes assumes a respective initialposition with respect thereto, said analyzer also being arranged foroperating said valve to isolate said pair of tubes from the being'svascular system and for coupling said pair of tubes together so that theposition of the blood in said pair of tubes changes, said analyzer alsobeing arranged for monitoring the blood position change in said tubesand calculating the viscosity of the blood based thereon.
 2. Theapparatus of claim 1 wherein said apparatus is adapted for effecting theviscosity measurement of circulating blood of a living being inreal-time.
 3. The apparatus of claim 2 wherein each of said tubes has asecond end and whereupon said apparatus additionally comprises means forventing said second ends of said pair of tubes to the ambientatmosphere.
 4. The apparatus of claim 2 wherein said analyzer detectsthe change in weight of said pair of tubes over time to effect saidmonitoring of the blood position change.
 5. The apparatus of claim 2wherein said respective initial positions comprise a first pre-testposition of a first column of blood with respect to one of said pair oftubes and a second pre-test position of a second column of blood withrespect to the other of said pair of tubes, said first pre-test positionand said second pre-test position being different from each other. 6.The apparatus of claim 5 wherein said pair of tubes are oriented uprightand wherein said first pre-test position comprises a first initialheight of said first column of blood and said second pre-test positioncomprises a second initial height of said second column of blood.
 7. Theapparatus of claim 6 wherein said analyzer detects the change in columnheight of said first and second columns of blood.
 8. The apparatus ofclaim 7 wherein said analyzer detects said change in column height bydetecting the time of flight of emitted signals toward the top of eachof said columns.
 9. The apparatus of claim 8 wherein said emittedsignals are acoustic signals.
 10. The apparatus of claim 6 wherein saidanalyzer includes a digital video camera for detecting the change incolumn height of said first and second columns of blood.
 11. Theapparatus of claim 6 wherein said analyzer detects the change inpressure of said first and second columns of blood over time to effectsaid monitoring of the blood position change.
 12. The apparatus of claim2 wherein said analyzer detects the change of volume in blood of saidpair of tubes to effect said monitoring of the blood position change.13. The apparatus of claim 2 further comprising environmental controlmeans, said environmental control means maintaining the blood in saidcapillary tube at substantially the same temperature of the living beingduring the time said analyzer couples said pair of tubes together. 14.The apparatus of claim 13 wherein said environmental control meansmaintains the blood in said pair of tubes at substantially the sametemperature of the living being during the time said analyzer couplessaid pair of tubes together.
 15. The apparatus of claim 5 wherein saidrespective initial positions of the blood in said pair of tubes isestablished by the operation of said analyzer.
 16. The apparatus ofclaim 6 wherein said first initial height and said second initial heightare established by the operation of said analyzer.
 17. The apparatus ofclaim 5 wherein said position of the blood in said pair of tubes changescomprises the movement of a respective level of said first and secondcolumns of blood moving in opposite directions and wherein said analyzerdetermines the difference value between said respective levels.
 18. Theapparatus of claim 6 wherein said analyzer determines the differencevalues of said heights of said columns of blood over time, known ash₁(t)-h₂(t) wherein h₁(t) is said height of said first column of bloodand h₂(t) is said height of said second column of blood.
 19. Theapparatus of claim 18 wherein said analyzer detects an offset of saidheights of said columns of blood, known as Δh, after monitoring theblood position change for a period of time.
 20. The apparatus of claim 2wherein said analyzer operates said valve to isolate said pair of tubesfrom the living being's vascular system while simultaneously couplingsaid pair of tubes together.
 21. The apparatus of claim 2 wherein saidanalyzer comprises a respective monitor for each of said pair of tubes,each of said respective monitors monitoring the blood position change insaid respective tubes.
 22. The apparatus of claim 21 wherein saidrespective monitors comprise respective light arrays and charge coupleddevices (CCDs).
 23. The apparatus of claim 22 wherein each of saidrespective light arrays comprises a plurality of light emitting diodesarranged in linear fashion to illuminate a respective tube along thelength of said tube.
 24. The apparatus of claim 2 wherein said pair oftubes is disposable.
 25. The apparatus of claim 2 wherein said valvemechanism is disposable.
 26. A method for determining the viscosity ofcirculating blood of a living being, said method comprising the stepsof: (a) providing access to the circulating blood of the living being toform an input flow of circulating blood; (b) dividing said input flow ofcirculating blood into a first flow path and a second flow path intowhich respective portions of said input flow pass, one of said first orsecond flow paths including a passageway portion having some knownparameters; (c) isolating said first and second flow paths from saidinput flow and coupling said first and second flow paths together sothat the position of the blood in each of said flow paths changes; (d)monitoring the blood position change in said first and second flow pathsover time; and (e) calculating the viscosity of said circulating bloodbased on said blood position change and on selected known parameters ofsaid passageway portion.
 27. The method of claim 26 wherein said step ofcalculating the viscosity of said circulating blood is conducted inreal-time.
 28. The method of claim 27 wherein said first and second flowpaths comprise respective columns of blood in upright positions and saidstep of monitoring the blood position change over time comprisesmonitoring the change in column height of said first and second columnsof blood over time.
 29. The method of claim 28 wherein said first andsecond columns are vented to ambient atmosphere.
 30. The method of claim27 wherein said first and second flow paths comprise respective columnsin upright positions and said step of monitoring the blood positionchange over time comprises monitoring the change in weight of said firstand second columns of circulating blood over time.
 31. The method ofclaim 27 wherein said first and second flow paths comprise respectivecolumns in upright positions and said step of monitoring the bloodposition change over time comprises monitoring the time of flight ofemitted signals towards the top of each of said columns.
 32. The methodof claim 31 wherein said emitted signals are acoustic signals.
 33. Themethod of claim 28 wherein said column height is monitored by a digitalvideo camera.
 34. The method of claim 27 wherein said first and secondflow paths comprise respective columns in upright positions and saidstep of monitoring the blood position change over time comprisesmonitoring the change in pressure of said first and second columns ofblood over time.
 35. The method of claim 27 wherein said first andsecond flow paths comprise respective columns in upright positions andsaid step of monitoring the blood position change over time comprisesmonitoring the change in mass of said first and second columns ofcirculating blood over time.
 36. The method of claim 27 wherein saidfirst and second flow paths comprise respective columns in uprightpositions and said step of monitoring the blood position change overtime comprises monitoring the change in volume of said first and secondcolumns of blood over time.
 37. The method of claim 27 furthercomprising the step of maintaining the temperature of said passagewayportion at substantially the same temperature of the living being duringsaid step of monitoring the blood position change in said first and saidflow paths.
 38. The method of claim 37 wherein said step of maintainingthe temperature further comprises maintaining the temperature of saidfirst and second flow paths at substantially the same temperature of theliving being during said step of monitoring the blood position change insaid first and said flow paths.
 39. The method of claim 28 wherein saidstep of dividing said input flow of circulating blood into a first flowpath and a second flow path comprises establishing a first pre-testlevel for said first column of blood and a second pre-test level forsaid second column of blood said first and second pre-test levels beingdifferent from each other.
 40. The method of claim 39 wherein said stepof calculating the viscosity comprises determining difference values ofsaid heights of said first and second columns of fluid over time, knownas h₁(t)-h₂(t) wherein h₁ is said height of said first column and h₂ issaid height of said second column.
 41. The method of claim 40 whereinsaid step of calculating the viscosity further comprises detecting anoffset of said heights of said first and second columns, known as Δh.42. An apparatus for effecting the viscosity measurement of circulatingblood in a living being, said apparatus comprising: a lumen arranged tobe coupled to the vascular system of the being; a pair of tubes havingrespective first ends and second ends, said first ends being coupledtogether via a capillary tube having some known parameters; a valve forcontrolling the flow of circulating blood from the being's vascularsystem to said pair of tubes, said valve being coupled to a second endof one of said pair of tubes and being coupled to said lumen; and ananalyzer, coupled to said valve, for controlling said valve to permitthe flow of blood into said pair of tubes whereupon the blood in each ofsaid pair of tubes assumes a respective initial position with respectthereto, said analyzer also being arranged for operating said valve toisolate said pair of tubes from the being's vascular system so that theposition of the blood in said pair of tubes changes, said analyzer alsobeing arranged for monitoring the blood position change in said tubesand calculating the viscosity of the blood thereon.
 43. The apparatus ofclaim 42 wherein said apparatus is adapted for effecting the viscositymeasurement of circulating blood of a living being in real-time.
 44. Theapparatus of claim 43 further comprises means for venting said secondend of said other one of said pair of tubes to atmosphere.
 45. Theapparatus of claim 43 wherein said analyzer detects the change in weightof said pair of tubes over time to effect said monitoring of the bloodposition change.
 46. The apparatus of claim 43 wherein said respectiveinitial positions comprise a first pre-test position of a first columnof blood with respect to one of said pair of tubes and a second pre-testposition of a second column of blood with respect to the other of saidpair of tubes, said first pre-test position and said second pre-testposition being different from each other.
 47. The apparatus of claim 46wherein said pair of tubes are oriented upright and wherein said firstpre-test position comprises a first initial height of said first columnof blood and said second pre-test position comprises a second initialheight of said second column of blood.
 48. The apparatus of claim 47wherein said analyzer detects the change in column height of said firstand second columns of blood.
 49. The apparatus of claim 48 wherein saidanalyzer detects said change in column height by detecting the time offlight of emitted signals toward the top of each of said columns. 50.The apparatus of claim 49 wherein said emitted signals are acousticsignals.
 51. The apparatus of claim 47 wherein said analyzer includes adigital video camera for detecting the change in column height of saidfirst and second columns of blood.
 52. The apparatus of claim 47 whereinsaid analyzer detects the change in pressure of said first and secondcolumns of blood over time to effect said monitoring of the bloodposition change.
 53. The apparatus of claim 43 wherein said analyzerdetects the change of volume in blood of said pair of tubes to effectsaid monitoring of the blood position change.
 54. The apparatus of claim43 further comprising environmental control means, said environmentalcontrol means maintaining the blood in said capillary tube atsubstantially the same temperature of the living being during the timesaid analyzer couples said pair of tubes together.
 55. The apparatus ofclaim 54 wherein said environmental control means maintains the blood insaid pair of tubes at substantially the same temperature of the livingbeing during the time said analyzer couples said pair of tubes together.56. The apparatus of claim 46 wherein said respective initial positionsof the blood in said pair of tubes is established by the operation ofsaid analyzer.
 57. The apparatus of claim 47 wherein said first initialheight and said second initial height are established by the operationof said analyzer.
 58. The apparatus of claim 46 wherein said position ofthe blood in said pair of tubes changes comprises the movement of arespective level of said first and second columns of blood moving inopposite directions and wherein said analyzer determines the differencevalue between said respective levels.
 59. The apparatus of claim 47wherein said analyzer determines the difference values of said heightsof said columns of blood over time, known as h₁(t)-h₂(t) wherein h₁(t)is said height of said first column of blood and h₂(t) is said height ofsaid second column of blood.
 60. The apparatus of claim 59 wherein saidanalyzer detects an offset of said height of said columns of blood,known as Δh, after monitoring the blood position change for a period oftime.
 61. The apparatus of claim 43 wherein said analyzer comprises arespective monitor for each of said pair of tubes, each of saidrespective monitors monitoring the blood position change in saidrespective tubes.
 62. The apparatus of claim 61 wherein said respectivemonitors comprise respective light arrays and charge coupled devices(CCDs).
 63. The apparatus of claim 62 wherein each of said respectivelight arrays comprises a plurality of light emitting diodes arranged inlinear fashion to illuminate a respective tube along the length of saidtube.
 64. The apparatus of claim 43 wherein said pair of tubes isdisposable.
 65. The apparatus of claim 43 wherein said valve mechanismis disposable.
 66. The apparatus of claim 43 wherein said analyzerfurther comprises a container, said container collecting an initialportion of the flow of circulating blood from the being's vascularsystem.
 67. The apparatus of claim 66 wherein said analyzer furthercomprises a detector adjacent an input port of said valve for detectingsaid initial portion of the flow of circulating blood from the being'svascular system.
 68. The apparatus of claim 67 wherein said valveisolates said container from the being's vascular system while couplingsaid pair of tubes to the being's vascular system.
 69. The apparatus ofclaim 61 wherein one of said respective monitors detects a predeterminedlevel in one of said pair of tubes in order for said analyzer to isolatesaid pair of tubes from the being's vascular system.
 70. A method fordetermining the viscosity of circulating blood of a living being, saidmethod comprising the steps of: (a) providing access to the circulatingblood of the living being to form an input flow of circulating blood;(b) directing said input flow into one end of a pair of tubes coupledtogether via a passageway having some known parameters, said input flowpassing through a first one of said pair of tubes, through saidpassageway and into a first portion of a second one of said pair oftubes in order to form respective columns in said first and secondtubes; (c) isolating said respective columns from said input flow sothat the position of the blood in each of said columns changes; (d)monitoring the blood position change in said respective columns of bloodover time; and (e) calculating the viscosity of the circulating bloodbased on said blood position change and on selected known parameters ofsaid passageway.
 71. The method of claim 26 wherein said step ofcalculating the viscosity of the circulating blood is conducted inreal-time.
 72. The method of claim 71 wherein said respective columns ofblood are in upright positions and said step of monitoring the bloodposition change over time comprises monitoring the change in columnheight of said respective columns of blood over time.
 73. The method ofclaim 72 wherein one end of said pair of tubes is vented to ambientatmosphere.
 74. The method of claim 71 wherein said respective columnsare in upright positions and said step of monitoring the blood positionchange over time comprises monitoring the change in weight of saidrespective columns of circulating blood over time.
 75. The method ofclaim 71 wherein said respective columns are in upright positions andsaid step of monitoring the blood position change over time comprisesmonitoring the time of flight of emitted signals towards the top of eachof said columns.
 76. The method of claim 75 wherein said emitted signalsare acoustic signals.
 77. The method of claim 72 wherein said columnheight is monitored by a digital video camera.
 78. The method of claim71 wherein said respective columns are in upright positions and saidstep of monitoring the blood position change over time comprisesmonitoring the change in pressure of said respective columns of bloodover time.
 79. The method of claim 71 wherein said respective columnsare in upright positions and said step of monitoring the blood positionchange over time comprises monitoring the change in mass of saidrespective columns of circulating blood over time.
 80. The method ofclaim 71 wherein said respective columns are in upright positions andsaid step of monitoring the blood position change over time comprisesmonitoring the change in volume of said respective columns of blood overtime.
 81. The method of claim 71 further comprising the step ofmaintaining the temperature of said passageway at substantially the sametemperature of the living being during said step of monitoring the bloodposition change in said respective columns.
 82. The method of claim 81wherein said step of maintaining the temperature further comprisesmaintaining the temperature of said respective columns at substantiallythe same temperature of the living being during said step of monitoringthe blood position change in said respective columns.
 83. The method ofclaim 72 wherein said step of directing said input flow of circulatingblood into one end of a pair of tubes comprises establishing a firstpre-test level for said first column of blood and a second pre-testlevel for said second column of blood, said first and second pre-testlevels being different from each other.
 84. The method of claim 83wherein said step of calculating the viscosity comprises determiningdifference values of said heights of said first and second columns offluid over time, known as h₁(t)-h₂(t) wherein h₁ is said height of saidfirst column and h₂ is said height of said second column.
 85. The methodof claim 84 wherein said step of calculating the viscosity furthercomprises detecting an offset of said heights of said first and secondcolumns, known as Δh.
 86. The method of claim 70 wherein said step ofproviding access to the circulating blood of the living being comprisescollecting a finite amount of the initial portion of said input flow ofcirculating blood into a container.
 87. The apparatus of claim 19wherein said analyzer calculates the viscosity using h₁(t)-h₂(t) and Δhto determine the consistency index, k, and the power law index, n, asgiven by:${{h_{1}(t)} - {h_{2}(t)} - {\Delta \quad h}} = {- \left\{ {{\left( \frac{n - 1}{n} \right)\alpha \quad t} + \left( {{\Delta \quad h} - h_{0}} \right)^{\frac{n - 1}{n}}} \right\}^{\frac{n}{n - 1}}}$

where$\alpha = {{- \frac{1}{2}}\left( \frac{4{kL}_{c}}{\rho \quad g\quad \varphi_{c}} \right)^{n}\left( \frac{n}{{3n} + 1} \right)\left( \frac{\varphi_{c}^{3}}{\varphi_{r}^{2}} \right)}$

and where h₀=h₁(O)-h₂(O); L_(c)=length of capillary tube; φ_(c)=insidediameter of said capillary tube; φ_(r)=diameter of said columns of bloodand where φ_(c)<<<φ_(r); ρ=blood density; and g=gravitational constant.88. The method of claim 41 wherein said step of calculating theviscosity further comprises using h₁(t)-h₂(t) and Δh to determine theconsistency index, k, and the power law index, n, as given by:${{h_{1}(t)} - {h_{2}(t)} - {\Delta \quad h}} = {- \left\{ {{\left( \frac{n - 1}{n} \right)\alpha \quad t} + \left( {{\Delta \quad h} - h_{0}} \right)^{\frac{n - 1}{n}}} \right\}^{\frac{n}{n - 1}}}$

where$\alpha = {{- \frac{1}{2}}\left( \frac{4{kL}_{c}}{\rho \quad g\quad \varphi_{c}} \right)^{n}\left( \frac{n}{{3n} + 1} \right)\left( \frac{\varphi_{c}^{3}}{\varphi_{r}^{2}} \right)}$

and where h₀=h₁(O)-h₂(O); L_(c)=length of said passageway portion;φ_(c)=inside diameter of said passageway portion; φ_(r)=diameter of saidfirst or second column of fluid and where φ_(c)<<<φ_(r); ρ=blooddensity; and g=gravitational constant.
 89. The apparatus of claim 60wherein said analyzer calculates the viscosity using h₁(t)-h₂(t) and Δhto determine the consistency index, k, and the power law index, n, asgiven by:${{h_{1}(t)} - {h_{2}(t)} - {\Delta \quad h}} = {- \left\{ {{\left( \frac{n - 1}{n} \right)\alpha \quad t} + \left( {{\Delta \quad h} - h_{0}} \right)^{\frac{n - 1}{n}}} \right\}^{\frac{n}{n - 1}}}$

where$\alpha = {{- \frac{1}{2}}\left( \frac{4{kL}_{c}}{\rho \quad g\quad \varphi_{c}} \right)^{n}\left( \frac{n}{{3n} + 1} \right)\left( \frac{\varphi_{c}^{3}}{\varphi_{r}^{2}} \right)}$

and where h₀=h₁(O)-h₂(O); L_(c)=length of capillary tube; φ_(c)=insidediameter of said capillary tube; φ_(r)=diameter of said columns, ofblood and where φ_(c)<<<φ_(r); ρ=blood density; and g=gravitationalconstant.
 90. The method of claim 85 wherein said step of calculatingthe viscosity further comprises using h₁(t)-h₂(t) and Δh to determinethe consistency index, k, and the power law index, n, as given by:${{h_{1}(t)} - {h_{2}(t)} - {\Delta \quad h}} = {- \left\{ {{\left( \frac{n - 1}{n} \right)\alpha \quad t} + \left( {{\Delta \quad h} - h_{0}} \right)^{\frac{n - 1}{n}}} \right\}^{\frac{n}{n - 1}}}$

where$\alpha = {{- \frac{1}{2}}\left( \frac{4{kL}_{c}}{\rho \quad g\quad \varphi_{c}} \right)^{n}\left( \frac{n}{{3n} + 1} \right)\left( \frac{\varphi_{c}^{3}}{\varphi_{r}^{2}} \right)}$

and where h₀=h₁(O)-h₂(O); L_(c)=length of passageway; φ_(c)=insidediameter of said passageway; φ_(r)=diameter of said first or secondcolumn of fluid and where φ_(c)<<<φ_(r); ρ=blood density; andg=gravitational constant.
 91. The method of claim 88 wherein said stepof calculating the viscosity, μ, further comprises using the determinedvalues of n and k in the equation: μ=k|{dot over (γ)}| ^(n−1) where$\overset{.}{\gamma} = {\left( \frac{{3n} + 1}{n} \right)\frac{8Q}{{\pi\varphi}_{c}^{3}}}$

and where Q=volumetric flow rate in said passageway portionφ_(c)=passageway portion diameter; and {dot over (γ)}=shear rate. 92.The apparatus of claim 89 wherein said analyzer calculates theviscosity, μ, using said determined values of n and k in the equation:μ=k|{dot over (γ)}| ^(n−1) where$\overset{.}{\gamma} = {\left( \frac{{3n} + 1}{n} \right)\frac{8Q}{{\pi\varphi}_{c}^{3}}}$

and where Q=volumetric flow rate in said capillary tube φ_(c)=capillarytube diameter; and {dot over (γ)}=shear rate.
 93. The method of claim 90wherein said step of calculating the viscosity, μ, further comprisesusing the determined values of n and k in the equation: μ=k|{dot over(γ)}| ^(n−1) where$\overset{.}{\gamma} = {\left( \frac{{3n} + 1}{n} \right)\frac{8Q}{{\pi\varphi}_{c}^{3}}}$

and where Q=volumetric flow rate in said passageway φ_(c)=passagewaydiameter; and {dot over (γ)}=shear rate.
 94. An apparatus for detectingthe movement of a fluid at plural shear rates using a decreasingpressure differential, said apparatus comprising: a fluid sourceelevated above a horizontal reference position; a flow resistor having afirst end and a second end, said first end being in fluid communicationwith the fluid source; a riser tube having one end coupled to saidsecond end of said flow resistor and another end being exposed toatmospheric pressure, said riser tube being positioned at an anglegreater than zero degrees with respect to said horizontal referenceposition; and a sensor for detecting the movement of the fluid, causedby said decreasing pressure differential, through said riser tube atplural shear rates as the fluid moves from the fluid source, throughsaid flow resistor and into said riser tube.
 95. The apparatus of claim94 wherein said flow resistor comprises a capillary tube.
 96. Theapparatus of claim 94 wherein said riser tube is positioned verticallywith respect to said horizontal reference position.
 97. The apparatus ofclaim 94 wherein the fluid is a non-Newtonian fluid.
 98. The apparatusof claim 97 wherein said movement of the fluid up the riser tubecomprises a rising fluid column and wherein said sensor monitors thechanging height of said rising column fluid over time, said height beingdefined as the distance between the top of said rising fluid column andsaid horizontal reference position.
 99. The apparatus of claim 98further comprising a computer, said computer being coupled to saidsensor and wherein said computer calculates the viscosity of the fluidbased on said changing height of said rising column of fluid over time.100. An apparatus for determining the viscosity of a non-Newtonian fluidover plural shear rates using a decreasing pressure differential, saidapparatus comprising: a non-Newtonian fluid source elevated above ahorizontal reference position; a capillary tube having a first end and asecond end, said first end being coupled to the non-Newtonian fluidsource; a riser tube having one end coupled to said first end of saidcapillary tube and another end being exposed to atmospheric pressure,said riser tube being positioned at an angle greater than zero degreeswith respect to said horizontal reference position; a sensor fordetecting the movement of the non-Newtonian fluid, caused by saiddecreasing pressure differential, through said riser tube at pluralshear rates as the non-Newtonian fluid moves from the non-Newtonianfluid source, through said capillary tube and into said riser tube, saidsensor generating data relating to the movement of the non-Newtonianfluid over time; and a computer, coupled to said sensor, for calculatingthe viscosity of the non-Newtonian fluid based on said data relating tothe movement of the non-Newtonian fluid over time.
 101. The apparatus ofclaim 100 wherein said riser tube is positioned vertically with respectto said horizontal reference position.
 102. The apparatus of claim 100wherein said non-Newtonian fluid is the circulating blood of a livingbeing and the non-Newtonian fluid source is the vascular system of theliving being.
 103. The apparatus of claim 94 wherein said analyzercalculates the viscosity, μ, using said determined values of n and k inthe equation: μ=k|{dot over (γ)}| ^(n−1) where$\overset{.}{\gamma} = {\left( \frac{{3n} + 1}{n} \right)\frac{8Q}{{\pi\varphi}_{c}^{3}}}$

and where Q=volumetric flow rate in said capillary tube φ_(c)=capillarytube diameter; and {dot over (γ)}=shear rate.